Download Argon is a chemical element represented by the symbol Ar.

Name: Wan Yuen Lam
(18) 3D
Argon is a chemical element represented by the symbol Ar. Argon has
atomic number 18 and is the third element in group 18 of the periodic table.
Argon is the third most common gas in the Earth's atmosphere, at 0.93%,
making it more common than carbon dioxide. Nearly all of this argon is
radiogenic argon-40 derived from the decay of potassium-40 in the
Earth's crust. In the universe, argon-36 is by far the most common argon
isotope, being the preferred argon isotope produced by stellar
nucleosynthesis in supernovas.
The name "argon" is derived from the Greek word αργον meaning "lazy" or
"the inactive one", a reference to the fact that the element undergoes
almost no chemical reactions. The complete octet (eight electrons) in the
outer atomic shell makes argon stable and resistant to bonding with other
elements. Its triple point temperature of 83.8058 K is a defining fixed
point in the International Temperature Scale of 1990.
Argon is produced industrially by the fractional distillation of liquid air.
Argon is mostly used as an inert shielding gas in welding and other
high-temperature industrial processes where ordinarily non-reactive
substances become reactive; for example, an argon atmosphere is used in
graphite electric furnaces to prevent the graphite from burning. Argon gas
also has uses in incandescent and fluorescent lighting, and other types of
gas discharge tubes. Argon makes a distinctive blue-green gas laser.
Spectral lines of argon